.TH std::basic_streambuf::showmanyc 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::basic_streambuf::showmanyc \- std::basic_streambuf::showmanyc

.SH Synopsis
   protected:
   virtual std::streamsize showmanyc();

   Estimates the number of characters available for input in the associated character
   sequence. underflow() is guaranteed not to return Traits::eof() or throw an
   exception until at least that many characters are extracted.

.SH Parameters

   \fI(none)\fP

.SH Return value

   The number of characters that are certainly available in the associated character
   sequence, or -1 if showmanyc can determine, without blocking, that no characters are
   available. If showmanyc returns -1, underflow() and uflow() will definitely return
   Traits::eof or throw.

   The base class version returns 0, which has the meaning of "unsure if there are
   characters available in the associated sequence".

.SH Notes

   The name of this function stands for "stream: how many characters?", so it is
   pronounced "S how many C", rather than "show many C".

.SH Example

    This section is incomplete
    Reason: no example

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

     DR    Applied to       Behavior as published              Correct behavior
                      underflow() is guaranteed not to  extended the guarantee to allow
   LWG 159 C++98      fail until                        at least
                      at least showmanyc() characters   showmanyc() characters to be
                      are supplied                      extracted

.SH See also

   in_avail  obtains the number of characters immediately available in the get area
             \fI(public member function)\fP
             optionally provides the number of characters available for input from the
   showmanyc file
   \fB[virtual]\fP \fI(virtual protected member function of std::basic_filebuf<CharT,Traits>)\fP


.SH Category:
     * Todo no example
